3 files changed, 47 insertions, 0 deletions
diff --git a/base/string_util.cc b/base/string_util.cc
index 63fec40..4ba8c4b 100644
--- a/base/string_util.cc
+++ b/base/string_util.cc
@@ -1140,6 +1140,31 @@ void SplitStringDontTrim(const std::string& str,
   SplitStringT(str, s, false, r);
 }
 
+template<typename STR>
+static STR JoinStringT(const std::vector<STR>& parts,
+                       typename STR::value_type sep) {
+  if (parts.size() == 0) return STR();
+
+  STR result(parts[0]);
+  typename std::vector<STR>::const_iterator iter = parts.begin();
+  ++iter;
+
+  for (; iter != parts.end(); ++iter) {
+    result += sep;
+    result += *iter;
+  }
+
+  return result;
+}
+
+std::string JoinString(const std::vector<std::string>& parts, char sep) {
+  return JoinStringT(parts, sep);
+}
+
+std::wstring JoinString(const std::vector<std::wstring>& parts, wchar_t sep) {
+  return JoinStringT(parts, sep);
+}
+
 void SplitStringAlongWhitespace(const std::wstring& str,
                                 std::vector<std::wstring>* result) {
   const size_t length = str.length();
diff --git a/base/string_util.h b/base/string_util.h
index 28c5d35..6ee079a 100644
--- a/base/string_util.h
+++ b/base/string_util.h
@@ -494,6 +494,10 @@ void SplitStringDontTrim(const std::string& str,
                          char s,
                          std::vector<std::string>* r);
 
+// Does the opposite of SplitString().
+std::wstring JoinString(const std::vector<std::wstring>& parts, wchar_t s);
+std::string JoinString(const std::vector<std::string>& parts, char s);
+
 // WARNING: this uses whitespace as defined by the HTML5 spec. If you need
 // a function similar to this but want to trim all types of whitespace, then
 // factor this out into a function that takes a string containing the characters
diff --git a/base/string_util_unittest.cc b/base/string_util_unittest.cc
index 7676f81..2b7634f 100644
--- a/base/string_util_unittest.cc
+++ b/base/string_util_unittest.cc
@@ -1299,6 +1299,24 @@ TEST(StringUtilTest, SplitString) {
   r.clear();
 }
 
+// Test for JoinString
+TEST(StringUtilTest, JoinString) {
+  std::vector<std::string> in;
+  EXPECT_EQ("", JoinString(in, ','));
+
+  in.push_back("a");
+  EXPECT_EQ("a", JoinString(in, ','));
+
+  in.push_back("b");
+  in.push_back("c");
+  EXPECT_EQ("a,b,c", JoinString(in, ','));
+
+  in.push_back("");
+  EXPECT_EQ("a,b,c,", JoinString(in, ','));
+  in.push_back(" ");
+  EXPECT_EQ("a|b|c|| ", JoinString(in, '|'));
+}
+
 TEST(StringUtilTest, StartsWith) {
   EXPECT_TRUE(StartsWithASCII("javascript:url", "javascript", true));
   EXPECT_FALSE(StartsWithASCII("JavaScript:url", "javascript", true));